Deadspawn Brian Lumley Necroscope #5 1991
Harry Keogh is a necroscope, he knows the thoughts of corpses in their graves.
Unfortunately for Harry, his talent works both ways. A maniacal murderer is on the loose, and the dead spirits of the madman's victims reach out to ask Harry Keogh to solve the crimes.
After the battles of Deadspeak, Harry Keogh has regained his necroscopic abilities. He can once again travel instantaneouslyh between places and times via the marvellous mathematics of the Mobius Continuum.
He can once again speak with the dead. But the necroscope's bargain with Faethor Farenczy, father of vampires, has sown the seed of Harry's own downfall - a vampire seed!
Deep in the recesses of Harry's mind grows a vampire that might someday be the greatest vampire of all. But now Harry is shunned by everyone, the living and the dead ... except for the tortured victims of a maniacal serial killer who cry out for justice.
Harry is the only person who can identify and find this vile murderer. It's high tide in a sea of blood but for Harry Keogh the tide has finally turned.
For even as he pursues the serial killer, he also fights the spawn inside him. His greatest battle is with himself and the plague he carries, for the necroscope is now a vampire.